Sunrun (RUN) shares experienced a dramatic pre-market plunge of 43.71% on Thursday, as the solar energy sector faced a double blow from political and financial fronts. The steep decline comes in the wake of President Donald Trump's tax bill advancing in the U.S. House of Representatives and multiple analyst downgrades targeting the company.

The Republican-backed tax bill, which is moving closer to a vote in the House, proposes to end many green-energy subsidies, including the elimination of a 30% federal credit for homeowners installing rooftop solar systems. This move is expected to significantly impact the solar industry, which has seen substantial growth over the past decade. Industry experts warn that the bill could deal a massive blow to companies like Sunrun that specialize in residential solar installations.

Adding to the pressure, Sunrun faced downgrades from multiple analysts. BNP Paribas Exane lowered its rating on Sunrun to Neutral from Outperform, adjusting its price target to $10 from $16. More dramatically, BMO Capital downgraded Sunrun to Underperform from Market Perform, slashing its price target to $4 from $9. These downgrades reflect growing concerns about the company's future prospects in light of the potential policy changes and market conditions.